1. Field of the Invention
The present invention relates to a finder device for a camera. More particularly, it relates to a finder device for a camera finder that uses a pentagonal mirror.
2. Description of Related Art
Camera finder devices are known which use pentagonal prisms and which use pentagonal mirrors. Devices that use pentagonal mirrors have an advantage over devices that use pentagonal prisms in that the pentagonal mirror devices can be made smaller and lighter than the pentagonal prism devices.
As described in Japanese Laid-Open Application 54-40634, finder devices that use pentagonal mirrors have first and second reflection surfaces. The finder device of the above Japanese application comprises a first reflection mirror that reflects the light rays that have passed through a condenser lens. A second reflection mirror then reflects the light rays that pass from the first reflection mirror to an eyepiece lens system. Finder devices that use pentagonal mirrors have empty spaces that are defined by the area between the first and second reflection mirrors, the condenser lens, and eyepiece lens system.
However, when empty spaces exist in a finder device, the following problems arise.
First, cloudiness can occur during the manufacture of the finder device inside the finder device, since the outside ambient air is enclosed in the finder device.
In particular, when a camera equipped with a finder device with empty spaces is taken from a low temperature environment to a room temperature environment (or, even more markedly, a high temperature environment), condensation can form on the interior of the finder device. Thus, the subject is unclear and cannot be readily seen using the finder device.
Second, since reflection mirrors are used, the reflective surfaces can oxidize or can accumulate dust due to contact with the outside ambient air. This also results in an unclear image.